From 2ce4f1e7ade1b5644e96bb19ee7a4156121bdf7b Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 15 Oct 2008 16:33:52 +0000 Subject: [PATCH] move PR1941 here. llvm-svn: 57586 --- lib/Target/README.txt | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/lib/Target/README.txt b/lib/Target/README.txt index 9831efbdf64..93e8c54979d 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -971,3 +971,17 @@ int main() { //===---------------------------------------------------------------------===// +Instcombine will merge comparisons like (x >= 10) && (x < 20) by producing (x - +10) u< 10, but only when the comparisons have matching sign. + +This could be converted with a similiar technique. (PR1941) + +define i1 @test(i8 %x) { + %A = icmp uge i8 %x, 5 + %B = icmp slt i8 %x, 20 + %C = and i1 %A, %B + ret i1 %C +} + +//===---------------------------------------------------------------------===// +